When considering compacted clay-based materials as engineered barrier in the immediate environment of a HLW container, not only the hydromechanical performance needs to be studied but also thermal and hydrochemical evolution needs to be known.
The influence of temperature on the hydrological, mechanical and chemical field, has been studied for each of these fields separately. However to be able to assess the overall performance of the clay barrier, it is the objective of this project to model the combined effect of temperature on the hydromechanical and hydrochemical field.
The development of codes for the simulation of multiphase flow under non-isothermal conditions and their application to the interpretation of the experimental work will be carried out.
When considering compacted clay based materials as engineered barriers in the direct environment of a high level radioactive waste (HLW) container, the hydromechanical, thermal and hydrochemical evolution of the barriers must all be studied. The influence of temperature on the hydraulical, mechanical and chemical fields, has been studied individually. However, to be able to assess the overall performance of the clay barrier, the combined effect of temperature on the hydromechanical and hydrochemical field must be examined.
In the field of thermomechanical modelling, a physical model incorporating all important phenomena in the behaviour of an unsaturated swelling clay has been built up, whilst in the thermochemical field, literature compiling has started. A first prototype cell has been constructed and validation tests have started.
A code to simulate multiphase flow under non-isothermal conditions will be developed and, on the one hand coupled to a chemical transport code and expansive material effects.
Tests will be carried out on ad hoc designed cells that will allow to determine the evolution of temperature, pressure and fluid concentration fields, produced in the clay barrier by heating of the central zone and by flow of water.
The thermo-mechanical and thermo-chemical models will be used in the interpretation of the above experiments and experiments carried out in complementary projects (contract No. FI2W-CT91-0098).
Funding SchemeCSC - Cost-sharing contracts